Reza paid $4,500 as a down payment on a car. She then made equal monthly payments of $250. Reza paid a total of $10,500 for her car. How many months did she make payments on the car and which function can be used to find the answer?
f (x) = 4,500 + 250 x; 24 months
f (x) = 4,500 minus 250 x; 3 months
f (x) = 4,500 x + 250; 3 months
f (x) = 4,500 x minus 250; 24 months